On the horizon

By
Peter N. Spotts /
April 21, 2005

Microbes point to life on mars

Biologists have discovered a community of microbes literally caught between a rock and a hard place. The results suggest that the best hope for finding evidence of past life on Mars may lie just beneath the surface of stones linked to volcanic or geothermal activity.

The microbial community appeared as a 1/2-inch thick green streak running just below the surface of rocks from the Norris Geyser Basin at Yellowstone National Park in Wyoming. Apparently, the bacteria gather their energy from the light that penetrates the crystalline rock and from chemicals in the highly acidic water found in the rocks' pores, according to the team that discovered the microbes, led by University of Colorado biologist Norman Pace.

It's the first time this type of bacteria has been seen as such a large component of a microbial community. The results are reported in Thursday's edition of the journal Nature.

The 'perfect' fluid

Smack gold ions together at high speed and what do you get? A new state of matter that appears to form the most perfect liquid ever seen. The experiment is expected to yield insights into conditions thought to have existed during the universe's first microseconds after the Big Bang some 13.7 billion years ago.

Four groups using the Relativistic Heavy Ion Collider at the Brookhaven National Laboratory on Long Island, N.Y., thought that by sending gold nuclei into head-on collisions with one another, they could generate a hot cloud of quarks and gluons. Quarks are the fundamental particles that make up protons and neutrons. Gluons bind the particles in an atom's nucleus.

The experiment hit temperatures the researchers expected - some 150,000 times hotter than the sun's core.

But instead of finding a cloud of ricocheting particles, the researchers were stunned to see the particles moving in a highly organized way - acting more like a liquid than a gas.

The teams reported their results this week at a meeting of the American Physical Society in Tampa, Fla.

It's a scenario Gulliver could appreciate: a swarm of Lilliputian creatures immobilizing a giant.

In this case, the creatures are ants found in trees in Brazil. A trio of biologists from the University of Toulouse in France have discovered that Allomerus decemarticulatus have learned to ambush prey that otherwise might fly or hop away. They say their discovery represents the first time anyone has linked a strategy of traps and ambushes to hungry ants.

Trees can be slim pickings for the nitrogen and protein ants need to survive; branches provide limited possibilities for foraging far and wide.

So the ants clip off tiny hairs from the plants' stems, then use a fungus to glue them together to build a spongelike platform. Ants hiding under the platform grab the prey through holes as it walks across. The hidden ants stretch the prey's legs and antennae in different directions so it can't move. Their cohorts outside the platform take care of the rest of the job. The group then coordinates its efforts to haul their meal back to the colony.

The team's observations appear in Thursday's edition of the journal Nature.